Large wheels used on vehicles such as earthmoving apparatus are typically of multi-piece construction which permit tires to be mounted thereon and locked into sealing engagement therewith without deforming the tires' inner edges or beads over protruding rims which are commonly found in automobile applications. The beads of tubeless tires mounted on such multi-piece wheel structures are axially restrained on one side by a restraining flange which is typically integral with a rim base which is radially adjacent one bead and on a second side by a second rstraining flange which is normally held in place by a bead seat band which is mounted radially between the rim base and the remaining tire bead. The bead seat band and the second flange are locked to the rim base by various means with means being provided for sealing between the bead seat band and the rim base so as to permit tire inflation. Other wheel structures exist in which the second restraining flange is integral with the bead seat band. Such structures also include a device for locking the flange and bead seat band into a desired configuration with the rim base as well as a seal which prevents air leakage between the bead seat band and rim base. Judicious disposition of the seal such that it is engaged by the locking device only when the locking device is properly assembled provides an indication of an improperly assembled locking device by preventing inflation of a tire mounted on such rim base. Such initial refusal to inflate is preferable to tire inflation at the time of mounting and tire deflation at a time subsequent thereto since suitable inflation equipment and/or wheel structure assemblying apparatus may not be as readily available when the utilizing vehicle is operating under service conditions as when the tire is initially mounted.
Other examples of wheel structures which prevent tire inflation when improperly assembled include U.S. Pat. Nos. 2,822,021 and 2,894,556 which respectively issued Feb. 4, 1958 and July 14, 1959. The aforementioned wheel structures include at least three components (restraining flange, bead seat band, and locking ring) in addition to the seal. Assembly of such multiple components with a tire mounted on a rim base necessitates simultaneous manipulation of those components into a desired, cooperative configuration in which the components are interlocked. The difficulty in manipulating the multiple components into such desired configuration increases rapidly with the number of components to-be-assembled. An example of a rim base structure assembled with one component is illustrated in a Goodyear Off-Highway Rim catalog whose number is EM75-6086. The rim type LW-LWD is illustrative of such structure and includes an integral restraining flange, locking ring, and bead seat band. For heavy construction vehicles a substantial upsetting moment tending to rotate the restraining flange about its surface of securement with the rim base or bead seat band can result from excessive air pressure in the tire and impact loading of such tire. Extension of the restraining flange under the mounted tire's adjacent bead provides a degree of resistance to such upsetting moment exerted by the mounted tire. However, under extreme conditions, additional axial support for the restraining flange is desirable.
Additional axial support of the restraining flange at a radial location beyond the mounted tire's inner edge is illustrated in U.S. Pat. No. 4,021,077 which issued May 3, 1977, U.S. Pat. No. 4,116,489 which issued Sept. 26, 1978, and U.S. Pat. No. 4,049,320 which issued Sept. 20, 1977. None of the aforementioned wheel structures illustrate any sealing means to prevent air leakage from a mounted tire's interior along the rim base since the tire's bead acts as its own seal against the rim base and cooperating lock ring. Moreover, such structures do not have provisions for preventing tire inflation when the locking ring is improperly assembled. U.S. Pat. No. 3,882,919 which issued May 13, 1975, illustrates a wheel structure which prevents tire inflation unless a locking device secures the restraining flange and bead seat band in proper configuration. While the performance of such wheel structure is admirable, the several components used therein are relatively expensive and present significant difficulty in simultaneous manipulation thereof during tire mounting and removal.
The present invention is directed toward providing a minimum number of wheel components which must be manipulated into a desired configuration during tire installation, provide structure to those components which provides high resistivity to upsetting moments exerted by the tire on the restraining flange, and supply means which cooperate with such components to prevent tire inflation when those components are improperly assembled.